Rebekah Brooks Described How to Hack a Phone, Witness Says

Witness Says Discussion Arose at Party for Prime Minister

LONDON—A witness in the high-profile U.K. phone-hacking trial testified that former News Corp executive Rebekah Brooks, at a party for the prime minister, described how to intercept cellphone voice mails. Ms. Brooks, according to the witness, also said phone hacking was common knowledge among journalists.

Dom Loehnis, a media industry headhunter, told the court that Ms. Brooks had described how to access voice-mail messages using a factory-default code. The two were seated next to each other, he said, at a 2010 birthday...